Ignition distributor adjustable from the exterior of the casing



Aug. 12, 1969 w. H. COOKSEY 3,461,253

IGNITION DISTRIBUTOR ADJUSTABLE FROM THE EXTERIOR OF THE CASING Filed May 11, 1967 2 Sheets-Sheet 1 Aug. 12, 1969 I w. H. COOKSEY 3,461,253

IGNITION DISTRIBUTOR ADJUSTABLE FROM THE EXTERIOR OF THE CASING Fild May 11, 1967 2 Sheets-Sheet 2 United States Patent M 3,461,253 IGNITION DISTRIBUTOR ADJUSTABLE FROM THE EXTERIQR OF THE CASING William Harold Cooksey, Walsall, England, assignor to Joseph Lucas (Industries) Limited, Birmingham, England Filed May 11, 1967, Ser. No. 637,655 Claims priority, application Great Britain, June 13, 1966, 26,245/66; Feb. 14, 1967, 7,007/67 Int. Cl. H01l1 19/02 US. Cl. 200-22 9 Claims ABSTRACT OF THE DISCLOSURE An ignition distributor for a road vehicle including a contact breaker assembly having fixed and movable contacts, there being provided means whereby the maximum gap between said contacts can be adjusted from the ex terior of the casing.

This invention relates to ignition distributors for use in road vehicles, of the kind comprising a casing, a rotatable shaft extending axially within the casing and carrying the distributor arm, and a contact breaker assembly also supported in the casing and including a fixed contact and a movable contact, said movable contact being movable into and out of engagement with said fixed contact in response to rotation of said shaft.

According to the invention a distributor of the kind specified is characterized in that means are provided whereby the maximum gap between said contacts can be adjusted from the exterior of the casing.

One example of the invention is illustrated in the accompanying drawings wherein:

FIGURE 1 is a diagrammatic part sectional view of an ignition distributor with parts thereof omitted for clarity,

FIGURE 2 is a sectional view on the line 2-2 in FIG- URE 1,

FIGURE 3 is a sectional view on the line 33 in FIG- URE 2,

FIGURE 4 is a fragmentary sectional view of a modification of the ignition distributor shown in FIGURE 1,

FIGURE 5 is a part sectional plan view of part of the distributor shown in FIGURE 4, and

FIGURE 6 is a perspective view of a connector shown in FIGURES 4 and 5.

Referring first to FIGURES 1, 2 and 3 of the drawings, the distributor includes a cylindrical casing 11 having journalled therein an axially extending shaft 12, the circumference of which defines a cam. Secured within the casing 11 is an annular plate 13, the shaft 12 extending through the central hole of the plate 13.

A second plate 14 having a portion 15 at right angles to the remainder thereof is arranged in contact with the lower surface of the plate 13 the portion 15 extending upwardly through a slot 16 formed in the plate 13. The plate 14 is pivotally engaged with the plate 13 at 17 and carries between the portion 15 and the pivot 17 a perpendicularly extending post 18. The post 18 extends through a slot in the plate 13 and through a hole 21 formed in a third plate 19, the post 18 serving to pivotally interconnect the plate 14 and the plate 19.

The plate 19 is of generally triangular shape and is formed with a contral hole 22 through which the shaft 12 extends. The plate 19 carries at each corner a short downwardly directed nylon post 23 which engages the plate 13 on its face remote from the plate 14 and serves to support the plate 19 for sliding movements on the plate 13.

The post 18 is stepped at its free end to define a shoulder 24 followed by a short shank 25. The shoulder 24 supports an annular washer 26 and the shank 25 1s 3,461,253 Patented Aug. 12, 1969 screw threaded to receive a nut 27 which maintains the washer 26 against the shoulder 24. A compression spring 28 is arranged between the washer 26 and the plate 19 and serves to urge the plates 19 and 14 towards each other igd into engagement with the opposite faces of the plate The pivot 17, the post 18 and the portion 15 are so aligned that a straight line passing through them would intersect at second straight line passing radially through the post 18 generally at right angles.

The casing 11 is formed with a shoulder 29 which is generally parallel with the portion '15 of the plate 14. A bolt 31 having a plain portion 32 and a narrower screw threaded portion 33, extends through the casing 11 at the shoulder 29, the part 33 being in screw threaded engagement with the portion 15. A spring 34 extends between the shoulder 29 and the portion 15 and urges the portion 15 away from the shoulder 29. Thus, rotation of the bolt 31 will move the plate '14 about the pivot 17.

The plate 19 carries an upwardly extending post 35 which constitutes a pivot for a movable contact member 37. The movable contact member 37 is of a conventional design and comprises an insulating body 38 engaged with the post 35 and having an integral projection 39 which rides on the cam surface of the shaft 12. The body 38 is urged to a position wherein the projection 39 engages the shaft 12 by a spring 41 anchored at one of its ends to the body 38 and at its other end to the plate 19 at 42, the spring 42 being insulated from the plate 19. The body 38 further carries a contact 43 in electrical connection with the spring 41, the contact 43 also being insulated from the plate 19.

The plate 19 carries a plate 19a on which is mounted a fixed contact 44 the plate 19 being electrically connected therewith, and the contact 44 being so positioned that in use it is periodically engaged by the contact 43 is response to rotation of the shaft 12.

Secured to the exterior of the casing 11 through an angle bracket 45 is a vacuum advance unit 46, having an operating rod 47 the free end of which extends through the casing 11 and is pivotally engaged with the plate 19 at 48.

In order to adjust contact gap, the engine of the road vehicle is allowed to run at tick over speed and the bolt 31 is rotated in a direction to move the contacts 43, 44 towards the shaft 12 until the engine stalls, the bolt 31 is then rotated in the opposite direction by a predetermined amount dependent on the pitch of the thread of the bolt 31 and the dimensions of the parts of the distributor to set the contact gap. Rotation of the bolt 31 causes the plate 14 to pivot about its pivot point 17, and by virtue of the pivotal connection between the plate 14 and the plate 19, the plate 19 will be caused to move. The plate 19 is however, constrained to near linear movement by virtue of its pivotal engagement with the rod 47, so that movement of the plate 19 alters the gap between the contacts 43, 44.

Automatic advance and retard adjustments to the timing of the distributor are effected in the following manner. The unit 46 is connected by means of a pipe (not shown) to the throttle edge of the carburetor of the engine. Variations in pressure at the throttle edge of the carburetor cause axial movements of the rod 47 in known manner and by virtue of the pivotal connection between the plate 19 and the rod 47 such axial movements cause the plate 1'9 to pivot about the post 18 and so alter the angular position of the projection 39 with respect to the cam surface on the shaft 12.

The dimensions of the slot 16 in the plate 13 are such that movement of the plate 14 is arrested by engagement of the portion 15 with the edge of the slot 16 before 3 either the plate 14 or the plate 19 engages the cam profile on the shaft 12.

In use the movable contact 43 is connected to a DC. supply by way of the spring 41 and the primary winding of the ignition coil, and the fixed contact 44 is earthed through the plate 19, the arrangement being such that as the shaft 12 rotates the contacts 43, 44 open and close to break and make the circuit through the primary winding of the ignition coil.

Referring now to FIGURES 4, 5 and 6; the plate 19 is C shaped instead of annular and the plate 19a is not used, the contact 44 being secured to a lug 48 upstanding from and integral with the plate 19.

In both modifications shown in FIGURES 4, 5 and 6 and in the example shown in FIGURES 1, 2 and 3 the contact 44 is earthed through the plate 19 and since the plate 19 is supported by the nylon posts 23 it is necessary to connect the plate 19 to the casing 11 electrically. For this purpose there is provided a lead 48 (FIGURES 4, 5 and 6) connected at one end to the casing 11 and carrying at its other end a connector 49. The connector 49 comprises an annular portion 51 which is engaged with the post 25 and which is trapped between the spring 28 and the plate 19. Integral with the portion is a cranked arm 52 the free end of which is electrically connected to the lead 48, the cranked portion of the arm 52 being engaged in a slot formed in the periphery of the plate 19 thereby preventing relative angular movement between the connector 49 and the plate 19.

The connector 49 and the lead 48 could be used in FIGURES 1, 2 and 3 instead of the conventional arrangement shown therein.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. An ignition distributor for use in road vehicles, comprising a casing, a rotatable shaft extending axially within the casing and carrying a distributor arm, a contact breaker assembly also supported in the casing and including a fixed contact and a movable contact, said movable contact being movable into and out of engagement with said fixed contact in response to rotation of said shaft, a first plate fixed to the casing, a second plate pivotally engaged with the first plate, a third plate pivotally engaged with the second plate and carrying the contact breaker assembly, and adjustable means operable from the exterior of the casing for adjusting the maximum gap between said contacts, said adjustment means acting on the second plate to cause the second plate to pivot relatively to the first plate, pivotal movement of the second plate relative to the first plate serving to move the third plate, by virtue of the interconnection of the second and third plate so that the contact breaker assembly is moved towards or away from the shaft to adjust the operating cap of the contact breaker contacts,

the third plate being pivoted relative to the second plate to adjust the ignition timing of the distributor.

2. An ignition distributor for use in a road vehicle comprising a casing, a rotatable shaft extending axially within the casting and carrying the distributor arm, a first plate fixed to the casing and surrounding the shaft, a second plate parallel with and pivotally connected to the first plate, a third plate parallel with and pivotally connected to the second plate, a contact breaker assembly carried by said third plate and operable in response to rotation of the shaft, the contact breaker assembly including a fixed contact and a movable contact and means for pivoting the second plate relative to the first plate to cause the third plate to move in a direction to adjust the operating gap of the contact breaker confacts.

3. A distributor as claimed in claim 3 wherein the third plate is pivotally connected to the second plate for angular movement about an axis offset from the axis of the shaft.

4. A distributor as claimed in claim 2 wherein the fixed contact of the contact breaker assembly is carried by a plate secured to the third plate.

5. A distributor as claimed in claim 2 wherein the third plate includes an integral lug to which the fixed contact of the contact breaker is secured.

6. A distributor as claimed in claim 2 wherein the third plate is generally C-shaped.

7. A distributor as claimed in claim 2 including a post extending from the second plate through the third plate and constituting the pivotal interconnection between the second and third plates, and a spring surrounding the post on the side of the third plate remote from the second plate and urging the third plate towards the second plate.

8. A distributor as claimed in claim 7 including an electrical connector having an annular portion surrounding the post and trapped between the spring and the third plate and a conductive lead through which the connector is connected to earth.

9. A distributor as claimed in claim 8 wherein the connector includes a further portion which is engaged with the third plate to render the connector non-rotatable relative to the third plate.

References Cited UNITED STATES PATENTS 2,9 14,625 11/ 1959 Heveran 200-3 1 2,945,923 7/1960 Julian et a1. 20031 3,242,274 3/ 1966 Sanden 20031 3,350,517 10/ 1967 Soeters ZOO-31 ROBERT K. SCHAEFER, Primary Examiner H. BURKS, Assistant Examiner 

